Radiological staging continues to remain the basis of a critical therapy of malignant lymphoma. As staging system, the Ann Arbor classification with some added modification is used. Up to now, CT is the imaging study of choice for staging and follow-up of cases of lymphoma. In future however, due to the advantages of the MRI, parts of the staging will be performed by MRI only. Imaging studies provide accurate measurement of extent of nodal disease. The detection of extra-nodal disease depends on the growth pattern and on the location. Focal lesions of sufficient size can be readily detected, diffuse infiltration is often missed. Computed tomography precisely reflects pathologic changes of lung involvement, but the findings are not specific. One weakness of the imaging studies is the low detection rate of splenic and hepatic involvement. Staging of gastrointestinal lymphoma has been improved by "hydro-CT" or "Hydro-MRI".